William h



W. H. DAVIS AND F. E. JOSS.

PHONUGRAPH TRANSMISSION ROD.

APPUCATIDN men IAY9.19IB.

Patented Aug. 12, 1919.

lwsmm UNITED STATES PAiIENT OFFICE.

WILLIAM H. DAVIS, OF BRONXVILLE, All D FREDBICK E. JOBS, OF BHDOKLYN, NEW

. YORK, ASSIGNORS TO LEKTOI'HONE CORPORATION, A CORPORATION 01' Dm- WARE.

PHONOGRAPH TRANSMISSION-BOD.

Specification of Letters Patent Patented Aug. 12, 1919- Applicatlon filed May 9, 1918. Serial No. 283,465.

To all whom it may concern:

Be it known that we, WILLIAM H. DAVIS and Fnnnmrn E. J'oss, both citizens of the United States, residing at, respectively, Bronxville, county of I estchester, State of New York, and borough of Brooklyn, county of Kings, city and State of New lork, have invented certain new and useful Improvements in Phonograph Transmission-Rods; and we do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

' This invention lelates to sound-reproduction, and it proposes, briefly, an nnproyed vibration transmission device for connection to the diaphra of a sound-reproducing mechanism, suc device being designed primarily for use in a machine or apparatus of the general t pe shown and described in U. S. Letters atent to Marcus C. Hopkins, No. 1,271,527 of July 2, 1918.

In machines of the character indicated, there is employed a large conical diaphragm of some strong and yet light vibratile material, which is freely exposed to unconfined air and has imparted to it, by means of a transmission connection, the vibrations imposed .upon or against a record or equivalent element. The arrangement in these nuu-hines is such that the diaphragm is subjected, along a line coincident with its axis, to the action of the aforesaid vibrations, and is thereby enabled to produce selfsustaining sound-waves substantially corrcspomling in intensity with the original sounddvavcs, so that the diaphragm thus takes the place not only of the usual sound-box, but also of its accompanying horn or like amplifier.

It has been found, however. that. some slight sound-distortion occurs in sound-re-' producing instruments constructed in accordance with the precise disclosure in the above-identified application. This may possibly be explained on the theory that the rod-like transmission device employed interferes in some way. due to the resonant naing over a considerable perio along the honic line of a record. Such abnormal vi ration of the rod most, obviously,

by accentuating the fundamental note of the rod itself, disturb the wave form of the sound then being sought to be regenerated and distort the qualit thereof u on regeneration. The essentia object of Sue present invention is, therefore, to overcome this distortion, produced, as just explained, by the interference of the natural vibrations of the transmission rod with the passage of the sound-vibrations through said rod to the diaphragm; such object being accomplished by the provision of a single transmission rod comprising at least two longitudinal sections or members arranged in endwise alinemeat and constructed of material of dissimilar resonance, one of such sections serving to neutralize or block the inde ndent' sound vibration emitted by the ot er .sec-. tion. The attainment in this way of the ob ject specified, that is, by the em loyment o a rod of the character describe or, in an event. the attainment of extremely adva tageous results in sound-reproduction along these lines by the use of such rod, as compared with the transmission connection utilined in the earlier constraction, is advanced 85' in consequence of a series of experiments, conducted with the utmost care and extend dof time. The precise theory which controls the situation, and which is really responsible for the improvements in question, may'actua'lly involve conditions and factors in addition to those stated above, and which possibly even difl'ersomewhat from'them, and the above theory is presented merel as a tentative explanation of the results 0 tained by or from the invention.

The accompanying drawing shows one form which the invention may take-when applied to, or installed in, a; Hopkins-type sound-reproducing machine; but it 'is to be u derstood that no limitation to the recise structural details therein discl is contemplated, excepting so far as may be' determined by the scope of the invention he subsequently claimed. Also, the inventim is not to be regarded as limited to. theme of its component parts or features inftlie particular dambinations illustrated in, said artsare susceptible of one another other Fig. 3 shows a 'sli htly'modified form of godfand" b Fig. 4 is a broken longitudinal section, on

a fui'ther'enlarged' scale, showing diptain of the parts illustrated in Fig. 1.

Referrin to'Fig. l, the invention, hich,

, as originally stated, comprises a rod-like tfitnsfihishibdmembert, is represented as applied" to, or: associated with, a: Hoplcinstype diaphragm 6, between which latter and the stylus holder- 7 ibis interposed The. die h m '6 is of the 'general' character dis lo s e d in the Hopkins patent, above identified, to which' reference may be had for acomplete description of its theory of 0 ration and. preferred dimensions. 'F or all present purposes, it is sullficient to state 'that the diaphragm comprises a conical portion of light, vibratile material which, when vibrated from a record or equivalent soundvibrated element, is thereby enabled to produce self-sustaining soundJwaves of substantially the same intensity as the original sound-waves, so that it replaces both the old sound-box and the usual accompanyin horn, as has previously been explaine The diaphragm is rigidly supported at its periphery between a pair of clamping rings 8 and 9, which are fastened together by screws, or in some other suitable manner,

and are carried by a spider 10, the hub of the latter being mounted upon one end of a tubular supporting bar 11. The bore 12 of this bar ext-ends thercthrough from end to end and provides a passage within which the transmission rod or intcrponent is rcceired. Tho op osite ends of the rod project beyond the liar 11, the rear end of said rod being cquip ed with a conical cap 13, which engages the apex of the conical or tion of the diaphragm. The'front em of the bar has fitted on it a cylindrical cap or sleeve 14, within which are accommodated the projecting front end of the transmission rod and a portion of the stylus holder 7, the aforesaid rod end being iere shown as connected to the stylus holder by means of a screw 15 which passes through a lateral eictcnsion on the holder and into the rod. The end of the holder in which the stylus is. actually received projects outwardly through an aperture in the ca 14, its will. be understood. The holder is preferably connected to the adjacent end of the tions 20 and 21, made vanta eously consist of inner and outer conical p ates of con'iparativcly stiff material, which clamp the apex of the diaphragm tightly between them, the hub portions of said plates being threaded mgcthcr as shown in Fig. 4, to couple theplates together. The inner of the two plates has its hub extended or elongated and provided with internal threads thus forming a cylindrical socket for the reception of a ccntraily-apertured plug 18, through which is inserted a screw 19 which projects a'tits inner end into a threaded aperture in the adjacc'ntend of the transmission rod 5.

Thetransmission rod, as stated above, constitutes the subject of the present invention, and comprise a plurality of separatelyconstructed sections or members connected together in endwise or axial aliucmcnt and formed of materials possessing different degrees of resonance. In the construction illustrated, the rod embodies two main secrcspectively, of nonmetallic and metallic materials, preferably wood and steel, the latter in the form of a strip of wire and, in addition to these two main sections, two short or auxiliary sections 22 and 23, which are, or may be, made of brass, the section 22 coupling together the adjacent endsof the aforesaid main sections, while the section 23 couples the front end of the wooden main section 20 with the stylus holder and is apertured to receive the end of the screw 15. The ends of the wooden section are provided with reduced, externaIly-threaded extensions 24, and the front end of the steel section 21 has a similar extension 25. these extensions 24 and 25 engaging in internally-tilrcadcd, axial sockets 26 and 27 in the coupling sections 23 and 22. The two main sections 20 and 21 may have different lengths, as is the case with the rod :3, represented in Figs. 1 and 2, in which the wooden section is approximately three times as long as the Steel section; or they may have substantially the same length. as in the rod illustrated in Fig. ingup the rod being the same in both instances. Still other relntive proportions may be adopted if desired. The non-metallie front section 20 preferably has a greater thickness than the metallic rear section 21, this holding good for both forms of the rod as shown and described.

0 claim:

1. A long, thin phonograph. transmission rod adapted to be connected at opposite ends with a stylus holder and a diaphragm and 3, the method of build to be vibrated by the travel of the stylus along a sound groove, co iprising a section inherently adapted to se upvindependent tonal vibrations during the travel of the stylus, and a section of differently-resonant material for neutralizing such independent vibrations, said sections alining and abutting end to end.

A long, thin phonograph transmission rod adapted to be connected at opposite ends with a stylus holder and a diaphragm and to be vibrated by the travel of the stylus along a, sound groove, c'omprising a metallic section inheiently adapted to up independent tonal vibrations during the travel of the stylus, and n non-metallic section forneutrulizil'ig such independent vibrations,

said sections nlining and abutting end to end.- 3. A long. thin phonograph transmission, rod adapted to be connected at opposite ends with a stylus holder and a diaphragm and to be vibrated by the travel of the stylus along a sound groove, comprising a metallic section inherently adapted to set up independent tonal vibrations during the travel adapted to be connected at opposite endswith a stylus holder and ii diizfhmgni and to be'vibruted during the trav of the stylus along a sound groove, said element coniprising a metallic section adapted to emit a dellnite, nudible sound-vibration independently as of the vibrations iingarted to it bywthe stylnsj during the travel twooden section for neutralizing such independent vibration. said sections alining and abutting end to end. 40

5. A long. thin phonograph transmission element adapted to be connected atopposite ends with a stylus-holder and a diaphragm nnd'to'be vibratethhyifi travel of the stylus along? a sound groove; comprising two sec- 4.:

tions of difl'erently resonant mnterials alining with each other andnbutting end to end.

" WILLIAM H. news.

FREDBICK E. JOSS.

erect, and a ,long, thin 

